关键词: 数字水印，四元数，四元数傅立叶变换

Abstract: Separate channel technictues performed on color images have the disadvantage of less ability to show connection between each channel during image processing. A new method to process color images with quaternion Fouricr transform was put forward in this paper. Firstly, ununiformity of each unit quaternion block in host image was calculated to pick up the potential block adaptively. Secondly, frectuency matrix of host color image was obtained by using quaternion Fouricr transforms. After that, the water marks were embedded into the amplitude of AC coefficient. Experimental results show that the image distortions from the watermark are spread into the three channels of a color host image and the proposed watermarking algorithm realizes a better trade off between imperceptibility and robustness.

Key words: Digital watermarking, Quatcrnion, Quatcrnion Fouricr transforms